Fix misalignment of menu items in Preferences > Save & Load menu

Checking for the layout alignment is not a reliable way to filter out
which items need the additional icon/text offset. Instead check if the
buttons are icon-only (which we rarely do, e.g. for collection colors in
the Outliner context menu).

source/blender/editors/interface/interface_widgets.c

@@ -2383,7 +2383,8 @@ static void widget_draw_text_icon(const uiFontStyle *fstyle,
         rect->xmin += 0.3f * U.widget_unit;
       }
     }
-    else if (ui_block_is_menu(but->block) && but->alignnr == 0) {
+    /* Menu items, but only if they are not icon-only (rare). */
+    else if (ui_block_is_menu(but->block) && but->drawstr[0]) {
       rect->xmin += 0.2f * U.widget_unit;
     }